The subject matter disclosed herein relates to power generators and, more particularly, to a system for cooling a power generator.
During the process of producing electricity, power generators create heat to be dissipated away from the generator to enable safe operation. Some generators use fluid cooling to dissipate this heat. In many generators, the fluid is a water or water solution. In the cooling systems the fluid is circulated through conduits proximate stator armature bars, wherein the fluid cools the stator to enable safe operation of the generator.
In some fluid cooled generators, a temperature of the bulk cooling fluid leaving the generator is monitored to ensure that the generator is operating safely. A fixed threshold operating temperature is compared to the detected temperature to determine if the generator is safely operating or should be shut down (or “tripped”). The bulk coolant temperature is an average of the temperatures of the coolant through many parallel cooling paths, and may not directly measure the hottest temperature. In situations where the temperature of the cooling fluid entering the generator may vary significantly, related to the ambient temperature and environment, the generator may be shut down even though the stator is operating safely. For example, in situations where the ambient temperature is elevated and the coolant entering the generator is likewise elevated, the generator fluid outlet temperature may be elevated, yet the stator remains operational and effectively cooled, as the hottest coolant in the winding is below an acceptable level. Such situations can cause the generator to be tripped unnecessarily when safely operating, thereby causing costly power plant outages.